nearly all strange emails with gifs attached are just spam. the .gif may not take up much space, but it still makes the email much bigger then a text only email. 1 email with a gif may not take up much space or use much bandwidth to send, but when you work out the millions of spam emails daily/weekly then all that space/bandiwdth all adds up. thats all the strange gif attachments are for, to make the spam use more bandwidth and space, thus be more of a problem (may not for the reciever, but for the companys who store emails and the internet itself for having to transmit so much spam it can be a problem).